preventing backscatter at the source

[Mark Nienberg]

Mark Sapiro wrote:

> The anti-backscatter militants will tell you you just can't have a
> backup MX unless it always has access to your user database. Since
> mail never goes to your backup unless your primary is down, there's
> no way the backup can call forward to the primary to validate an
> address. But, the bright side of this is you are just rejecting the
> backup's mail at SMTP time, so the backscatter DSN is the ISP's
> problem ;)

Interesting.  A lot of spammers seem to send deliberately to secondary or teriary MXs 
instead of the primary even when the primary is up and running, in hopes of that it 
will not be as well protected.  So most of the time the backup at my ISP could call 
forward (but I doubt that it is, I'll have to check).

Mark Nienberg